= malloc, mallocz, smalloc, free, realloc, calloc: kernel memory allocators

    void* malloc(ulong size)

    void* mallocz(ulong size, int clr)

    void* smalloc(ulong size)

    void* realloc(void *p, ulong size)

    void* calloc(ulong n, ulong szelem)

    void  free(void *p)

These functions allocate memory from the mainmem memory pool.
All but smalloc (which sleeps) may safely be called by inter‐
rupt handlers.

Malloc returns a pointer to a block of at least  size  bytes,
initialised  to  zero.   The  result  is  aligned on a 32-bit
boundary.  Mallocz is similar, but only clears the memory  if
clr is non-zero.

Smalloc  returns  a  pointer  to  a block of size bytes, ini‐
tialised to zero.  If the memory is  not  immediately  avail‐
able, smalloc retries every 100 milliseconds until the memory
is acquired.

Calloc returns a pointer to a block of  memory  of  at  least
n*szelem bytes, initialised to zero.

Realloc changes the size of the block pointed to by p to size
bytes, if possible without moving the  data,  and  returns  a
pointer  to  the block.  The contents are unchanged up to the
lesser of old and new sizes, and any new space  allocated  is
initialised to zero.  If p is a null pointer, realloc returns
the equivalent of malloc(size).

The argument to free is a pointer to a block of memory  allo‐
cated  by one of the routines above, which is returned to the
allocation pool, or a null pointer, which is ignored.

== diagnostics
All functions except smalloc return a null pointer  if  space
is unavailable.

== see ALSO
xalloc(10.2)